The present invention relates to fuel pump modules for use in an automotive fuel system. More particularly, the present invention relates to an improved fuel pump module which improves the alignment between the jet pump nozzle and the throat.
In recent years, an increasing number of automobiles have included fuel systems wherein the fuel pump for the system is incorporated within the fuel tank of the automobile. In such systems, the fuel pump is typically located within a canister or reservoir in the fuel tank and the reservoir is overfilled with fuel supplied from a fuel return line which returns an oversupply of fuel from the automobile""s engine (a return system) or from the excess fuel from a pressure regulator (returnless system). As the fuel returns from the engine through the return line, it is typically routed through a venturi orifice or jet pump and into an inlet passage leading into the canister or reservoir. The inlet passage is submerged in fuel within the fuel tank and the fuel exiting the venturi or jet pump creates a pressure drop in the area of the inlet passage such that additional fuel from the fuel tank is conveyed into the canister or reservoir along with the fuel jetted from the venturi orifice or jet pump into the inlet passage.
The venturis or jet pumps in use today are generally formed as fixed nozzles wherein the orifice size is optimized for the anticipated use. When the barrel of the jet pump nozzle is extended in length to facilitate the installation of the jet pump to the fuel tank and/or optimize the position of the throat opening, the increase in length will exaggerate the angular deviation located at the outlet of the nozzle. This angular deviation is caused by the designed dimensional tolerances, the manufacturing tolerances and the manufacturing procedures. Any misalignment of the jet pump nozzle and the throat will adversely affect the performance of the pump by potentially causing a severe loss in suction performance of the jet pump, ultimately leading to poor driveability of the vehicle.
The continued development for the jet pumps for the fuel systems has been directed to jet pump designs and jet pump manufacturing procedures which reduce and/or eliminate misalignment between the jet pump nozzle and the throat, especially when an extended length jet pump nozzle is being utilized.
The present invention provides the art with an improved jet pump nozzle design which incorporates an alignment device which minimizes misalignment between the jet pump nozzle and the throat. In one embodiment, a tapered elliptical slide engages a groove to properly align the jet pump nozzle with the throat prior to ultrasonic welding of the jet pump to the fuel tank. In another embodiment of the present invention, a hook formed on the jet pump nozzle is designed to engage a slot formed on the tank to align the jet pump nozzle with the throat prior to the ultrasonic welding of the two components. In yet another embodiment of the present invention, a tapered peg formed on the tank is designed to engage a slot formed on the jet pump prior of the ultrasonic welding of the two components. In still yet another embodiment of the present invention non-circular ultrasonic welding grooves are formed on the two components. The mating of the two non-circular ultrasonic weld grooves prior to ultrasonic welding of the components ensures the alignment between the jet pump nozzle and the throat.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.